The interconnecting pipeline in an oilfield has been running for 19 years with serious corrosion. In order to reduce the number of corrosion perforations and lower economic losses, it is necessary to identify the causes of corrosion. Through the comprehensive analysis on the corrosion perforation site investigation and pipeline inspection results, operation data, fluid parameters and other data, it is found that the key factors for the corrosion of the pipeline body, girth weld and anchor pier are as per the following: the high corrosiveness of the fluid medium in the pipeline, the damage to the outer corrosion protection layer, the disparities between the girth weld metal and the main body metal, the irrational construction technology, complex stress action and so on. The rectifications are made for the interconnecting pipeline in that oilfield in the following steps. The first step is to replace the 5km outbound pipeline of the starting depot. The second one includes removing all the existing fixed anchor piers and installing replaceable anchor piers where necessary, and implement appropriate corrosion protection measures between anchor piers and pipeline contact points. The third step is to make sure that the internal and external inspection and repair and reinforcement of the pipeline shall be properly carried out. The fourth step is to strengthen the girth welds with carbon fiber where the strength is found to be not up to standard and improve the welding quality. Analysis on causes of corrosion and rectification measures will ensure safe and stable pipeline operation and prolong theservice life of the pipeline.